The present invention concerns focussing systems for photographic still or motion-picture cameras, the systems being of the type which in dependence upon true camera-to-subject distance automatically adjust the subject-distance setting of the camera's exposure objective and/or provide the user with an indication of the direction in which he should manually move the camera's focus adjuster member. More particularly, the invention concerns focussing systems of the type in which a signal source directs towards the subject a beam of electromagnetic radiation, with a receiver matched to the signal source and receiving the radiation reflected back from the subject. The receiver comprises radiation detectors located side by side, and an optics located in front of the side-by-side radiation detectors, shiftable relative to the radiation detectors, and coupled to the exposure objective or focus adjuster structure of the camera to be shifted in dependence upon the subject-distance setting of the objective; alternatively, the optics just mentioned is non-shiftable, and the side-by-side radiation detectors are mounted shiftable and coupled to focus adjuster structure of the exposure objective.